How do you define IQ and how much do you care?

For me, IQ ("Image Quality") relates to the technical quality of the photo, almost always resolution, DR, and/or noise, and does not include scene or composition. For example, I consider this photo, which I like a lot, to be "low IQ":

whereas this photo, which I also like a lot, to be "higher IQ":

(I tried to find two similar photos with different "IQ levels")

Clearly, it is easily possible to prefer a "low IQ" photo to a "high IQ" photo -- "high IQ" doesn't mean "better", at least to me it doesn't. That said, I don't think I've ever seen a photo "ruined" by "high IQ" whereas I've seen several photos "ruined" by "low IQ", in the way I think about IQ. However, I allow for the fact that if a boring "high IQ" photo had been taken (or, at least, processed) in a "low IQ" manner, I'd have liked it better. Indeed, I process many of my photos to have "lower IQ" because I like the "low IQ" look better for certain photos. I would go so far as to say that sometimes the "high IQ" photo is simply boring but the "low IQ" version of the same photo is far more interesting.

By taking the initial photo with as "high IQ" as you can and "lowering the IQ" in processing you typically have more artistic options, as it's difficult, and often impossible, to take a "low IQ" photo and make it "higher IQ". Thus, my desire for equipment that can deliver "higher IQ" -- you can even use settings on your "high IQ" equipment that result in "low IQ" photos, but the reverse is not true.

Lastly, for those who IQ in the way I use the term has no bearing, or, at least, any camera delivers IQ that is "high enough", why do you choose one camera over another rather than just the cheapest camera, or even just use a smartphone? Ergonomics rule over all else? Or are there certain operational differences that are "must haves", like animal tracking?

Do distinguish between IS and IQ, Image Satisfaction is only observable by oneself while resolution , contrast and out of focus behaviour as well as gradation and colur can be measured and prerceived by anyone.in my case I am better at judging framing in front of te computer screen than out were I record my snaps, hence I demand exposures where smaller areas can be enlarged without severe loss of acuity.

p.

"IQ" is defined here:

www.imatest.com/imaging/cpiq/

Spatial Frequency Response (SFR)
Lateral Chromatic Displacement (LCD)
Color Uniformity
Local Geometric Distortion
Texture Blur
Visual Noise
Chroma Level

I care about Spatial Frequency Response, Texture Blur ... and Chroma Level to an extent.

Imatest Version 2021.1 Supports CPIQ v2 measurements:

Auto Exposure.

I don't use Auto Exposure much.

The use of "IQ" by itself is so often used without qualification ... "high IQ", "low IQ" tell us nothing specific.

And IS, image satisfaction is unmeasurable. Mostly depending on what is being depicted-. Hence various quality metrics may be irrelevant for some.

p.

Works for me!

I use it all the time (typically use Av mode) and adjust with EC and/or ISO setting as needed.

True, just as saying "She's hot!" tells us nothing specific. It's just a different way to say "would". : )

Absolutely! For example, I don't care about distortion for most of the photos I take or see (although photos that are not level bug me!). But, yeah, IS is absolutely subjective, far more than IQ, I should think.

You have to be careful not to define IQ entirely by how a camera forms an image, or by the desire to have an absolute logical framework because that fits one's worldview. Though IQ is predominantly a technical exercise about extracting the maximum performance from the camera we mustn't forget that this is viewed through a human eye and so "translated" by human perception, (or that CP is Camera Phone 😉). There is a crossover between the two.

For instance if we get too technical and only look at how the camera captures then we tend to measure IQ by how the camera records the actual values it's presented with, we measure it against scientific reality. If we include perception then we compare those recorded values more towards memory, and our memories tend to exaggerate those aspects we think defined the scene.

For a high IQ shot we also need to get that bit right, how we exaggerate reality that little bit so it matches more closely how we remember and even prefer things to be.

As we go back and forth, is there a credible Standard for IQ - other than CPIQ which is specifically for camera phones?

If not, "IQ" is whatever Chuck Norris says it is ...

Sad thing about internet fora is that, as soon as someone posts an opinion not backed by a credible reference, someone else will be right back with an un-backed rebuttal. Shoot, even if you post a formula from a credible source such as ISO, there will often be someone along to tell you how wrong that is ...

Ok then, define Chroma Level. See if you don't get back to, "how the tri-chromatic human eye sees colour with a bias towards the perceptual preference of an imperfect memory..."

I don't have to. It is defined here - www.imatest.com/docs/cpiq-support/#chroma ...

... which makes no mention of or even imply how the tri-chromatic human eye sees colour with a bias towards the perceptual preference of an imperfect memory.

CIELAB colour space?

Yes.

Another in that vogue: DPR, digital photographic rendition. ...😀